1. Field of the Invention
The present invention relates to an electronic endoscope and, more particularly, to the structure of each of cables for connecting between a light-source-side connector and a processor portion, between an intermediate member of an electronic endoscope and the light-source-side connector, and between the intermediate member and a processor portion.
2. Description of the Related Art
A related electronic endoscope apparatus irradiates light, which is supplied from a light source portion (light source unit) through a lightguide, from a front end portion of an electronic endoscope (scope). Then, an observation object illuminated with the irradiated light is imaged by, for example, a CCD (Charge Coupled Device) serving as a solid-state image pickup device mounted at the front end thereof. Subsequently, an image pickup signal output from the CCD is supplied to a processor unit through a cable. Then, predetermined signal processing is performed on the image pickup signal at the processor unit. Thus, an image of the observation object, such as a digestive organ, can be displayed on a monitor.
FIG. 5 illustrates the configuration of a part of a related electronic endoscope apparatus. As illustrated in FIG. 5, the related electronic endoscope apparatus has a light source unit 1 and a processor unit 2. A cable 3 of an electronic endoscope (not shown) is connected to the light source unit 1 through a light source connector 4. A branch cable 5 branched off from the light source connector 4 is connected to the processor unit 2. That is, a lightguide and a signal line are provided in the cable 3 to extend from a front end portion of the electronic endoscope. The lightguide is connected to the light source unit 1 through the light source connector 4, while the signal line is provided in the branch cable 5 through the light source connector 4 and is connected to the processor unit 2 by inserting the electric connector 6 into a connector receptacle 7a. 
Further, such a kind of an electronic endoscope apparatus is configured so that different kinds of electronic endoscopes can be connected to the processor unit 2. Thus, the processor unit 2 is provided not only with a connector receptacle 7a, to which the aforementioned electric connector 6 is connected, but with another connector receptacle 7b to which a connector of another kind of an electronic endoscope is connected.
FIG. 6 illustrates the configuration of an outer-sheath of the branch cable 5 is displayed. This outer-sheath is constituted by a spiral tube 8 formed by spirally winding an elongated metallic strip body, a net 9 which covers the exterior of the spiral tube 8, and a synthetic resin outer skin 10 which covers the exterior of the net 9.
However, the branch cable 5 used in the related electronic endoscope apparatus has a structure in which the spiral tube 8 is covered with the net 9, as illustrated in FIG. 6. Consequently, the branch cable 5 is relatively hard, so that the cable 5 can be neither freely bent nor largely twisted. Thus, sometimes, the electric connector 6 cannot smoothly be attached to the connector receptacle 7a. That is, because an attaching position (position in a rotational direction), at which the electric connector 6 is attached to the connector receptacle 7a, is preliminarily determined, the electric connector 6 sometimes cannot smoothly be inserted into the predetermined position in a case where the branch cable 5 is hard.
Further, in a case where different kinds of electronic endoscopes are connected to the processor unit 2, the attaching position of the light source connector 4 does not change, whereas the attaching position of the electric connector 6 is changed from the position of the connector receptacle 7a to that of the connector receptacle 7b. Even in such a case, the related electronic endoscope apparatus has a problem that because the branch cable 5 is relatively hard, the electric connector 6 cannot smoothly be inserted into the connector receptacle.
On the other hand, as described in JP-A-8-76025, some related device is configured so that a junction portion of a cable of an endoscope has a rotating mechanism. FIG. 7 illustrates the configuration of this endoscope. This endoscope is configured so that a cable 13 provided to extend from an operating portion 12 has a junction portion 14, that branch cables 15 and 16 are branched off from the junction portion 14, and that the light source connector 17 is attached to one of the branch cables 15, while the electric connector 18 is attached to the other branch cable 16. Additionally, a rotating mechanism constituted by a sliding groove and a pin is provided in the junction portion 14. Consequently, the branch cables 15 and 16 are rotated by the rotating mechanism with respect to the cable 13. Thus, the twist of the cable can be absorbed by the rotating mechanism.
However, even in such a configuration, in a case where the branch cables 15 and 16 are fixed to the junction portion 14, and where the light source connector 17 is fixed to the light source unit, the movement (drawing-out) of the electric connector 18 is restricted. On the other hand, in a case where the branch cables 15 and 16 are fixed to the junction portion 14, and where the electric connector 18 is fixed to the processor unit, the movement (drawing-out) of the light source connector 18 is restricted. Thus, the related electric endoscope apparatus has a problem that the light source connector 17 and the complicated rotating mechanism cause high cost.